Conventional tie rod ends are manufactured in a manner that prevents access to interior components for service of the tie rod ends when significantly worn after extended use. In such a conventional structure, the housing of the unit has an open bottom end of reduced diameter presenting an inward projecting lip or flange against which the lower race is seated around the opening through which the stem or stud of the ball member projects. The ball portion of the ball member is received between the lower race and a corresponding upper race, which together provide spherically contoured surfaces conforming against the ball at positions thereover and thereunder so that the ball can rotate in any of three orthogonal axes to allow rotation of the stem and tilting thereof in any direction. In this conventional structure, the top end of the housing is permanently closed off, for example by pressing a cap into the body over a crush-washer surmounting the upper race to crush the washer to a level providing a desired degree of tightness of the upper race against the ball, and then crushing a retaining lip into position over the perimeter of the closed cap. The housing is thus permanently closed at both ends, preventing access to the internal components. Accordingly, the internal components cannot be replaced when worn, and so the entire assembly must be replaced with a new joint, as the internal components cannot be accessed, at least not in a manner that is non-destructive to the housing to allow re-use thereof.
Some serviceable designs for tie rod ends and ball joints have been proposed.
U.S. Pat. No. 6,908,251 teaches tie rod ends and ball joints where an externally threaded retainer member is engaged into the housing from the upper end thereof to close the housing and tighten the upper race against the ball member. The threaded engagement of this retainer member to the housing allows removal for access to the internal components. However, there is some concern that even with use of a set screw to secure the retainer member in place, the threaded coupling may come loose during use of the tie rod end or ball joint.
U.S. Patent Application Publication No. 2009/0238636 teaches tie rod ends and ball joints that likewise use a threaded retainer member, but additionally add a retaining ring and snap ring engaged to the housing overtop of the threaded retainer member. While the design does allow access to internal components for service, and prevents backing off of the threaded retainer member by way of the added rings, there still remains room for improvement.
Applicant of the present application has developed novel spherical joints useful to provide reliable and serviceable rod ends, tie rod ends and ball joints.